Abstract
Background: Hodgkin lymphoma (HL) is one of the most common, and one of the most curable cancers in adolescents and young adults (AYAs) (15-39 years). Despite excellent outcomes in the majority of patients, the burden of long-term morbidity and mortality persists. Prior analyses of patients treated for HL before the year 2000 have reported mortality rates as high as 30% by 20 years. Further, this mortality risk has historically differed across different racial and ethnic groups. Over the past decade, cooperative groups have expanded the use of risk-adapted, response-based treatment in an effort to maintain high cure rates, while simultaneously reducing the burden of late effects. We examined long-term survival in AYAs with HL treated after the year 2000.
Methods: We used the National Cancer Institute Surveillance, Epidemiology, and End Results registry data for 18 regions in the United States (SEER18) to examine survival in AYAs with a confirmed diagnosis of HL between 2000 and 2015. We obtained overall and cause-specific survival estimates for each year after cancer diagnosis (up to 15 years) for each racial/ethnic group with corresponding 95% confidence intervals. From these yearly survival estimates, we calculated the percentage of deaths not attributed to HL at 10- and 15-years after cancer diagnosis.
Results: The final analysis included 16,868 HL patients. Racial/ethnic subgroups included: non-Hispanic white (NHW; 11,016, 65%), Hispanic (2,753, 16%), non-Hispanic black (NHB; 2,131, 13%), and Asian/Pacific Islander (API; 968, 6%) AYAs with HL. Across the full cohort, the 10-year and 15-year overall survival probabilities were 90% (95% confidence interval [95%CI]: 89 - 91) and 87% (95% CI: 86 - 88), respectively. At 10- and 15-years, overall survival was highest for NHWs (10-year: 92%: 15-year: 88%) and APIs (91%; 86%) compared to Hispanics (87%; 85%) and NHBs (82%; 78%). Overall survival, cause-specific survival, and percentage of deaths not attributed to HL by race/ethnicity are presented in the Figure. In the first year after diagnosis, 22% of deaths were due to causes other than primary disease, with the percentage of deaths not attributed to HL higher in NHWs and APIs than Hispanics and NHBs. At most time points after cancer diagnosis, a higher proportion of NHW (vs. NHB, Hispanic and API) patients died from causes other than HL. By 10 years after diagnosis, 25% of NHW patients died due to causes other than HL, vs. 20% in API, 17% in NHB, and 15% in Hispanic patients. By 15 years, 33% of all deaths were not attributed to HL. This was observed most dramatically in the NHW cohort in whom 40% of all deaths were not HL-related, compared to 24% of deaths in the NHB cohort and 26% - 27% of deaths in the Hispanic and API groups.
Conclusion: In AYAs diagnosed with HL between 2000 and 2015, NHB patients had worse survival compared with NHW and API patients. The higher probability of survival in NHW patients was accompanied by a consistently higher proportion of non-cancer related death in this cohort both 10- years and 15-years after diagnosis. Studies are needed to evaluate risk factors for both short- and long-term mortality in AYAs, and to examine how these risks differ across racial/ethnic groups. Findings also suggest that despite increasing use of response-adapted therapy over the past two decades, all AYAs with HL remain at risk of death in the decades following therapy, further highlighting the need for long-term follow-up of this at-risk patient population.
Muffly:Adaptive Biotechnologies: Research Funding; Shire Pharmaceuticals: Research Funding.
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